Musket

Muskets are semi-common and haven't completely replaced the bow. Most varieties have a snaplock, or wheellock, mechanism and are smoothbore firing .45 to .50 caliber round balls, buck and ball, and buckshot
A musket used for shooting birds is known as a fowling piece.
Breech loading versions exist but they're ludicrously expensive custom pieces used by rich nobility.

Mechanics & Inner Workings

The flint strikes the frizzen, generating sparks, and igniting the main powder charge